Gainer confirmed during a phone interview with CQ Roll Call that his office is proceeding with instructions to review computers used by committee staffers to investigate the CIA's interrogation techniques and detainee practices during the George W. Bush administration.

"Some of it will be done in-house and some of it will be contracted out," he said of the investigation. "It’s not the first time that we’ve done forensic work on a computer, remember ... that’s a large part of our organization."

As sergeant-at-arms, Gainer serves as the chamber's top law enforcement officer, overseeing all aspects of security, including cyber threats.

"But, there are experts who do this day-in and day-out, and there is no doubt that we’ll get help from others on this," he continued.

Intelligence Chairwoman Dianne Feinstein, D-Calif., first revealed her suspicions in a stirring March 11 floor speech , in which she alleged the CIA had interfered at the secret facility set up in Northern Virginia for the committee's investigation.

Reid has also raised concerns about the broader implications of the CIA's actions, a fact he mentioned in his letter.

Gainer said he spends a "substantial portion" of each day on security issues — coordinating with the House, the Capitol Police and other federal agencies — and this investigation is his newest task.